chromium iii iodide is an insulating, intrinsic 2D Ising ferromagnet exhibiting a Curie temperature of 61 K. It is a layered and easily cleavable material that consists of edge-shared CrI6 octahedra in a honeycomb lattice. Single-layer crystals exhibit a small trigonal distortion of the octahedra and monoclinic stacking. The observed magnetism results from a weak interlayer coupling and the intrinsic nature of the material can be explained by a low energy density.

Thermodynamic modeling of the iodide compound led to the rational prediction of applicable experimental conditions for the growth of the crystalline material. As a result, chromium(III) bromide micro- and nanosheets were grown on yttria stabilized zirconia (YSZ) substrates by pure chemical vapor transport (CVT). The optimum vapor transport conditions were deduced from the simulation results and they were confirmed by the obtained crystal growth data. The resulting micro- and nanosheets were characterized by scanning electron microscopy (SEM).

Ultrathin sheets of CrBr3 show dark gray according to SEM secondary electron image contrast. In addition, the SEM-energy dispersive X-ray analysis confirms that the obtained crystals contain a close 1:3 stoichiometry of chromium and chloride. Moreover, the thickness of these structures was found to be approximately 10 nm. This value is in good agreement with the theoretical calculations based on the dissociation equilibria of trioxochlorochromate(VI) and chromic acid (see the attached file).